vsukhin/deferclient

Defer Panic Client

Defer Panic client

Defer Panic Client Lib.

• Panic Handling - Let the client catch and log any panic you get to your own dashboard.

• Error Handling - Handle your errrors - but log them.

• HTTP latency - DeferClient can log the latencies of all your hard hit http requests.

• HTTP RPM - Aggregate all the response codes for all your HTTP requests over time.

• Micro Services Tracing - DeferClient can log queries to other services so you know exactly what service is slowing down the initial request!

• Database latency - Get notified of slow database queries in your go app.

• Metrics - See:

  • go routines
  • memory
  • usage
  • gc runs && pause times
  • cgo
  • file descriptors over time

  and more automatically in your own dashboard.

• Custom K/V - Got something we don't support? You can log your own k/v metrics just as easily. Use this client.

Translations:

• 简体中文
• Русский

Installation

go get github.com/deferpanic/deferclient/deferstats

api key

Get an API KEY via your shell or signup manually here:

 curl https://api.deferpanic.com/v1.13/users/create \
        -X POST \
        -d "[email protected]" \
        -d "password=password"

HTTP Examples

Here we have 3 examples:

• log a fast request
• log a slow request
• log a panic

package main

import (
	"fmt"
	"github.com/deferpanic/deferclient/deferstats"
	"net/http"
	"time"
)

func panicHandler(w http.ResponseWriter, r *http.Request) {
	panic("there is no need to panic")
}

func fastHandler(w http.ResponseWriter, r *http.Request) {
	fmt.Fprintf(w, "this request is fast")
}

func slowHandler(w http.ResponseWriter, r *http.Request) {
	time.Sleep(2 * time.Second)
	fmt.Fprintf(w, "this request is slow")
}

func main() {
	dps := deferstats.NewClient("v00L0K6CdKjE4QwX5DL1iiODxovAHUfo")

	go dps.CaptureStats()

	http.HandleFunc("/fast", dps.HTTPHandlerFunc(fastHandler))
	http.HandleFunc("/slow", dps.HTTPHandlerFunc(slowHandler))
	http.HandleFunc("/panic", dps.HTTPHandlerFunc(panicHandler))

	http.ListenAndServe(":3000", nil)
}

You can see that our slow request triggers our latency threshold and winds up in our dashboard while the panic is also caught and winds up in the dashboard.

The default latency threshold is 500ms.

The client works perfectly fine in non-HTTP applications:

Log Errors

If you want to log your errors use this method. deferstats.Wrap will log the bactrace and the error and ship it up to deferpanic immediately.

package main

import (
        "errors"
        "fmt"
        "github.com/deferpanic/deferclient/deferstats"
        "time"
)

var (
        dps *deferstats.Client
)

func errorTest() {
        err := errors.New("danger will robinson!")
        if err != nil {
                dps.Wrap(err)
                fmt.Println(err)
        }
}

func panicTest() {
        defer dps.Persist()
        panic("there is no need to panic")
}

func main() {
        dps = deferstats.NewClient("v00L0K6CdKjE4QwX5DL1iiODxovAHUfo")

        errorTest()
        panicTest()

        time.Sleep(time.Second * 20)
}

Database Latency

package main

import (
  "database/sql"
  "github.com/deferpanic/deferclient/deferstats"
  _ "github.com/lib/pq"
  "log"
  "time"
)

func main() {
  dps := deferstats.NewClient("v00L0K6CdKjE4QwX5DL1iiODxovAHUfo")

  _db, err := sql.Open("postgres", "dbname=dptest sslmode=disable")
  db := deferstats.NewDB(_db)

  go dps.CaptureStats()

  var id int
  var sleep string
  err = db.QueryRow("select 1 as num, pg_sleep(0.25)").Scan(&id, &sleep)
  if err != nil {
    log.Println("oh no!")
  }

  err = db.QueryRow("select 1 as num, pg_sleep(2)").Scan(&id, &sleep)
  if err != nil {
    log.Println("oh no!")
  }

  time.Sleep(120 * time.Second)
}

We have additional database ORM wrappers:

• gorp
• sqlx
• mgo
• gorm

Micro-Services/SOA Tracing

Got a micro-services/SOA architecture? Now you can trace your queries throughout and tie them back to the initial query that started it all!

We set the HTTP header X-dpparentspanid in each request to trace requests throughout your architecture.

Example

User Facing Service

package main

import (
  "fmt"
  "github.com/deferpanic/deferclient/deferstats"
  "io/ioutil"
  "net/http"
)

func handler(w http.ResponseWriter, r *http.Request) {

  // just pass your spanId w/each request
  client := &http.Client{}
  request, err := http.NewRequest("POST", "http://127.0.0.1:7070/internal", nil)
  if err != nil {
    fmt.Println(err)
  }

  request.Header.Add("X-dpparentspanid", deferstats.GetSpanIdString(w))

  resp, err := client.Do(request)
  if err != nil {
    fmt.Println(err)
  }

  defer resp.Body.Close()
  body, err := ioutil.ReadAll(resp.Body)

  fmt.Fprintf(w, string(body))
}

func main() {
  dfs := deferstats.NewClient("v00L0K6CdKjE4QwX5DL1iiODxovAHUfo")

  go dfs.CaptureStats()

  http.HandleFunc("/", dfs.HTTPHandlerFunc(handler))
  http.ListenAndServe(":9090", nil)
}

Slow Internal API

package main

import (
	"encoding/json"
	"github.com/deferpanic/deferclient/deferstats"
	"net/http"
	"time"
)

type blah struct {
	Stuff string
}

func handler(w http.ResponseWriter, r *http.Request) {
	time.Sleep(510 * time.Millisecond)

	stuff := blah{
		Stuff: "some reply",
	}

	js, err := json.Marshal(stuff)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	w.Header().Set("Content-Type", "application/json")
	w.Write(js)
}

func main() {
	dfs := deferstats.NewClient("v00L0K6CdKjE4QwX5DL1iiODxovAHUfo")

	go dfs.CaptureStats()

	http.HandleFunc("/internal", dfs.HTTPHandlerFunc(handler))
	http.ListenAndServe(":7070", nil)
}

Notice that when you wrap your http handlers w/the deferstats httphandler we instantly tie the front facing service to the slow internal one.

Set Environment

Want to monitor both staging and production? By default the environment is set to 'production' but you can us a different environment just by setting the environment variable to wahtever you wish and all data will be tagged this way. Then you can change it from your settings in your dashboard.

package main

import (
	"github.com/deferpanic/deferclient/deferstats"
	"time"
)

func main() {
	dfs := deferstats.NewClient("v00L0K6CdKjE4QwX5DL1iiODxovAHUfo")
	dfs.Setenvironment("some-other-environment")

	go dfs.CaptureStats()

	time.Sleep(120 * time.Second)
}

Set AppGroup

Many deferPanic users are using micro-servіces/SOA and sometimes you want to see activity from one application versus all of them.

You can set this via the AppGroup variable and then toggle it from your settings in your dashboard.

package main

import (
  "github.com/deferpanic/deferclient/deferstats"
  "time"
)

func main() {
  dfs := deferstats.NewClient("v00L0K6CdKjE4QwX5DL1iiODxovAHUfo")
  dfs.SetappGroup("queueMaster3000")

  go dfs.CaptureStats()

  time.Sleep(120 * time.Second)
}

Disable posting to deferpanic for test/dev environments

Pretty much everyone needs to disable the client in a dev/test mode otherwise you are going to be overwhelmed with notifications.

You can disable it simply by using the setter function SetnoPost.

package main

import (
  "github.com/deferpanic/deferclient/deferstats"
  "time"
)

func main() {
  dfs := deferstats.NewClient("v00L0K6CdKjE4QwX5DL1iiODxovAHUfo")
  dfs.SetnoPost(true)

  go dfs.CaptureStats()

  time.Sleep(120 * time.Second)
}

Dependencies

There are currently no dependencies so this should work out of the box for container runtimes like docker && rocket.

Documentation

See https://godoc.org/github.com/deferpanic/deferclient for documentation.

Defer Panic Client